diff --git a/app/schemas.py b/app/schemas.py
index f571bbc3..7d49bf17 100644
--- a/app/schemas.py
+++ b/app/schemas.py
@@ -155,6 +155,7 @@ def labels_tags_is_valid(cls, v):
         if v is not None:
             if len(v) == 0:
                 raise ValueError("`labels_tags` cannot be empty")
+        return v
 
     @model_validator(mode="after")
     def product_code_and_category_tag_are_exclusive(self):